This proposal aims to develop, validate, and apply an innovative model to determine the cost-effectiveness of alternative prostate cancer screening and treatment strategies. In addition, the proposal seeks to understand how the cost- effectiveness of prostate cancer screening and treatment may be altered by expected changes mortality rates from other causes over the coming decades and by new insights into appropriate accounting for future costs in medical cost-effectiveness analysis. Thus, the specific aims are: 1. To determine the effectiveness, costs, and cost-effectiveness of prostate cancer screening and treatment using an innovative model that captures a range of important aspects of the disease that have been neglected by previous cost-effectiveness analyses and to validate this model using data concerning prostate cancer incidence and mortality collected by the SEER program and other data sources. Examples of the important aspects of prostate cancer that have been neglected by previous analyses that we will model include: (1) tumor heterogeneity and progression rates by grade, (2) the discrepancy between clinical and pathologic stage, including the possibility of metastases in the absence of advanced localized disease, (3) the ability of screening and treatment to affect the prevalence of prostate cancer, and the related importance of modeling differences in cohort-specific screening histories, (4) the effect of benign prostatic hypertrophy and other prostate symptoms and their management on the detection of prostate cancer, (5) the effects of the serial correlation of tumor detectability by PSA or DRE on the value of repeated screening, and (6) the potential for screening programs at different frequencies and ages to have very different effects on costs and effectiveness. 2. To assess how the effects and cost-effectiveness of screening and treatment at different ages will be altered by the declines in mortality from other causes of death that are expected to occur over the next several decades. 3. To assess how the cost-effectiveness of prostate cancer screening and treatment will be affected by the appropriate inclusion of future medical and non-medical costs in cost- effectiveness analysis.